Consumption of poultry contaminated with Campylobacters has been implicated as a major source of human infection. Therefore, removal of these organisms from the poultry food chain has been a significant objective of Campylobacter research.
Campylobacters typically grow and colonize in the avian gut environment. Colonization has been reported in chickens, ducks, pigeons, quail, ostriches and turkeys. Colonization of poultry does not result in disease but is commensal in nature.
The use of a competitive exclusion culture to exclude Salmonella or Campylobacter from the digestive tract of a bird has been described in U.S. Pat. No. 6,491,910. The efficacy of this method against Campylobacter appears variable. In ovo vaccination with heat killed cells of Campylobacter jejuni has been described by Noor et al. (British Poultry Science, 1995. 36(4): 563-73) and by Noor (Jurnal Ilmu Ternak Dan Veteriner, 1998. 3(4): 264-269). In ovo immunization of chickens with flagellin and whole cell protein antigens of Campylobacter jejuni has also been reported by S. Noor et al. (Jurnal Ilmu Ternak Dan Veteriner, 2000. 5(2): 119-124). Efforts have also been made in order to identify the genes involved in colonization (Ziprin et al., Abstracts, Poultry Science Association meeting, Aug. 8-11, 1999, Springdale, Ariz.). See also, Rice, 1997, “Campylobacter jejuni in broiler chickens: colonization and humoral immunity following oral vaccination and experimental infection”, Vaccine 15(17-18): 1922-1932, wherein killed Campylobacter cells are administered; and Ziprin et al, 2002, Current Microbiology 44(3): 221-223, wherein chicks were vaccinated post-hatch with viable but non-colonizing strains.
Prior to the present invention, there has been no effective immunization strategy that employs in ovo administration with live Campylobacter cells.